Options traders who bet the Trump administration would renege on its promise to tariff raw copper imports are cashing in big.

The once-mighty premium U.S. copper enjoyed over the global benchmark slid on Thursday as markets clawed back months of gains in hours of frenzied trading after President Donald Trump surprised markets with pared-back tariffs.

The president stopped short of putting a 50 percent tariff on refined copper, as he had threatened earlier this year. The market reaction was swift anyway and prices tumbled.